A conventional loudspeaker is described referring to FIG. 9, a conventional loudspeaker comprises a magnetic circuit A consisting of a magnet 1, a top plate 2, a bottom plate 3 and a yoke 4. The loudspeaker also comprises a voice coil 5 provided in the gap of the magnetic circuit A, a frame 6, a diaphragm 7, and a damper 8.
The magnetic circuit A is fixed to the frame 6 by inserting a plurality of protrusions 4a provided at the outer edge of yoke 4 into a plurality of fixing holes 6a provided in the frame 6, and caulking, or swaging, them.
Many of the recent car-borne audio equipment are also boasting of a greater output in their compact overall dimensions. With an aim to make the magnetic circuit A of a speaker small and compact, a magnet of neodymium, which has a higher magnetic energy as compared with conventional ferrite magnets, is increasingly used for the magnet 1. This requires subtle work during assembly of a loudspeaker in connecting the magnetic circuit A with the frame 6.